This invention relates to the packaging of spring units. More specifically, this invention relates to a method of roll-packing plural spring units.
It is known in the art to pack spring units for use in making mattresses by winding a length of flexible web material, e.g., disposable paper or re-usable hessian around a mandrel and feeding the spring units successively into the nip between the growing roll and the traveling web material. The spring units are compressed as they are drawn into the roll, and the result is that the roll-packed springs have a much reduced volume as compared to conventionally stacked spring units.
One type of machine known for this purpose has a winding mandrel to which a holding bar is bolted by its ends for holding the leading end of a packing web material. An upwardly moveable pressure roller is mounted above the mandrel so as to define therewith an entry nip for the web material. The web material is fed from a reel supported at the rear of the machine over the pressure roller and on to the mandrel. An operator standing at the front of the machine feeds springs into the entry nip.
Another machine for packing bedding springs is seen in U.S. Pat. No. 4,669,247. This patent describes packing spring units into a roll with a web of paper or other reusable material. A similar spring packing machine is seen in U.S. Pat. No. 2,114,008, in which a roll of wrapping paper is fed along a table and into a wrapping mechanism whereat spring assemblies are placed upon the paper and fed into the machine by the paper movement.
All of these prior art machines compress and wrap springs in a single web of paper or reusable material which separates the multiple layers of spring units in a roll and maintains the springs in a compressed state for shipment from a spring manufacturer to a mattress manufacturer. This conventional roll-packing technique tends to be expensive. Either large amounts of paper that will be eventually disposed of are used to wrap springs at a cost to the spring manufacturer which is often passed on to the mattress manufacturer, or much more expensive recyclable packaging is used to roll and ship springs. The recyclable material which is used to roll and ship springs must be thereafter shipped back to the spring manufacturer who, again, may incur the cost of shipping back the material and may pass that expense on to the mattress manufacturer. In addition, recyclable spring packaging material has a relatively short life span, albeit longer than paper packaging.
Therefore, it has been one objective of the present invention to reduce the cost of packaging and shipment of spring units.
It has been another objective of the present invention to provide a method of packaging spring units without using conventional paper or reusable packaging methods.
It has been a further objective of the present invention to provide a method of packaging a spring unit in which the spring unit is packaged in insulator material that will not be disposed of but, rather, be used by the mattress manufacturer in mattress production.
The preferred embodiments of the present invention accomplish these objectives with a method of packaging a resilient spring unit such as a plurality of interconnected coil springs in which first and second webs of spring insulator material are first attached to the spring unit so as to be located against the spring unit top and bottom surfaces and thereafter roll-packed for shipment from a spring manufacturer to a mattress manufacturer who simply unrolls the spring units and cuts the insulator material between the spring units, the spring units having the insulator material attached thereto to be used in mattress manufacture so as to eliminate the need to roll-pack the spring units with disposable paper or expensive reusable material.
The spring unit has a uniform depth defined by a generally planar top first surface and a parallel generally planar bottom second surface. The spring unit has a longitudinal dimension or length defined by a pair of opposed parallel end surfaces and a transverse dimension or width defined by a pair of opposed parallel side surfaces. The longitudinal dimension or length is generally greater than the transverse dimension or width of the spring unit as in most bedding products. However, a square spring unit in which the longitudinal and transverse dimensions are equal may also be packaged using this inventive method.
The method of the present invention comprises providing first and second web rolls of insulator material spaced from one another. The first web roll comprises a first web of spring insulator material, e.g., woven or non-woven material, wound about a core. Similarly, the second web roll comprises a second web of spring insulator material wound about a core.
Each of the first and second webs of insulator material have a pair of opposed side edges defining a width of the web which is wider than the spring unit""s transverse dimension. Each web across its width has a pair of opposed side portions and a central portion between the side portions.
The first web of insulator material is passed over and located against the first surface of the spring unit, and the second web is passed under and located against the second surface of the spring unit. The longitudinal dimension of the spring unit is generally parallel to the opposed side edges of the first and second webs which are generally parallel to one another.
In a first preferred embodiment, the first and second webs are folded back upon themselves around the top and bottom turns of the edgemost coil springs of the spring unit so that the opposed side portions are located against the surface of the central portion located against the spring unit. These side portions are then bonded, welded or otherwise secured to the central portion. In a second preferred embodiment, the side portions of the first web are bonded or welded to the adjacent side portions of the second web so as to form a tight fitting sleeve in which the spring unit is securely located. The spring unit with the first and second webs secured there against constitutes a bedding product.
The final step in the method of the present invention is to draw the bedding product into a roll-packing machine in which the bedding product is compressed and rolled onto a dowel whereafter the bedding product is maintained in this rolled and compressed state for shipment to a mattress manufacturer.
These and other objectives and advantages of this invention will be readily apparent from the following description of the drawings.